Figure 1.

Breast tumor classification according to the CIT classification into six subgroups of tumors. (a) Heatmap representing the expression of the 256 genes (nine clusters of genes represented by vertical color bars on the left of the heatmap) through the six groups. (b) Principal component analysis (PCA) of the samples of the coreset according to the 256 gene signature. The first principal component (PC1) represents the combined expression of the three transversal clusters (ER, AR and cell cycle), the second component (PC2) differentiates LumB and NormL. (c) Distribution of mean expression levels of the three transversal gene clusters (ER, AR and Cell Cycle) over the six main molecular subgroups. (d) Comparison of the CIT classification with those obtained using the Sorlie, Hu, Parker and Jönsson systems.